Fabrication of magnetic core/shell hydrogels via microfluidics for controlled drug delivery

[Display omitted] •Magnetic thermosensitive hydrogels are prepared using microfluidic device.•These hydrogels can respond to both magnetic and thermal stimulation.•These hydrogels can be used as drug carriers.•Drugs can be released on demand by controlling the switch of the magnetic field. Magnetic thermosensitive hydrogels stand out in the field of magnetic hyperthermia because of their dual responses of both magnetic and thermal stimulations. In this work, the microfluidic technology was utilized to prepare magnetic thermosensitive hydrogels. Two anticancer drugs, camptothecin and doxorubicin hydrochloride, were loaded in the core and shell layers of generated double emulsions to achieve the simultaneous delivery of hydrophobic and hydrophilic drugs. The targeted delivery of composite drugs could be achieved by embedding Fe3O4 nanoparticles in the shell layer of double emulsions. In addition, under the effect of a high frequency alternating magnetic field, the thermal effect of magnetic nanoparticles caused by the loss processes during the reorientation of the magnetization would increase the temperature of hydrogel and change its swelling state, thus achieving sustained and controlled release of encapsulated drugs. Alternatively, the heat generated by magnetic nanoparticles under a high frequency alternating magnetic field could locally heat up the tissue, thus realizing hyperthermia. The results of cellular cytotoxicity assay indicated that these combined drug loaded hydrogels provided sufficient cytotoxicity in the cancer cell inhibition, and it was also demonstrated that poly (N-isopropyl acrylamide) (PNIPAM) could be used as a safe carrier for drug delivery systems.